Delaying toxigenesis of Clostridium botulinum by sodium lactate in ‘sous-vide’ products

Abstract

The effect of sodium lactate and storage temperature on toxigenesis by proteolytic (Pr) and nonproteolytic (Np) Clostridium botulinum spores inoculated in processed ‘sous‐vide’‐type beef, chicken breast and salmon was explored. Three g samples of beef and salmon homogenates with 0, 2.4 and 4.8% (w/w) lactate and of chicken with 0, 1.8 and 3.6% (w/w) lactate were placed in 24‐well tissue culture plates. The samples were inoculated with 104 spores of pools of Pr (4A + 2B + 2F strains) or Np (4B + 4E strains), vacuum‐packaged in barrier bags, and stored at 16 and 30°C for Pr and at 4, 8, 12 and 30°C for Np for up to 90 d. Lactate at 2.4% in beef and 1.8% in chicken delayed toxigenesis by Np for 40 d at 12°C and by Pr for 28 d at 16°C. Delaying toxigenesis for similar periods of time in salmon required 4.8% lactate and 12°C for Np, and 2.4% lactate and 16°C for Pr. Increasing levels of lactate and decreasing temperature significantly delayed toxigenesis of Cl. botulinum in the ‘sous‐vide’ products.

Safety Evaluation of Sous Vide-Processed Products with Respect to Nonproteolytic Clostridium botulinum by Use of Challenge Studies and Predictive Microbiological Models

“…Another alternative to improve safety would be to add additional hurdles to products. Biopreservatives, such as nisin and organic acids, are known to have an antibotulinal effect (33,43,45). However, even a slight change in formulation or processing conditions warrants a safety evaluation by challenge tests since the predictive models available to date appear to frequently provide misleading predictions.…”

The microbiology of cold smoked salmon

“…Sallam and Samejima (2004) found no significant effect on LAB when ground beef was treated with NaL alone, but a combination of NaL and NaCl resulted in >3 log units lower LAB counts after 21 days storage at 2 C compared to the untreated control, and 2.5 and 2.0 log units, respectively, compared to NaCl and NaL treated samples. NaL significantly delayed toxigenesis of C. botulinum in vacuum packaged beef, chicken, and salmon, although salmon required higher concentration or lower storage temperature than the former two products to give similar effect (Meng & Genigeorgis, 1994), indicating that results from meat studies cannot be easily transferred to fish and CSS.…”

“…Addition of lactate salt at a concentration of 4.8% in RTE 'sousvide'salmon delayed non-proteolytic C. botulinum toxin production !40 days when stored below 12 C (Meng & Genigeorgis, 1994). In order to obtain similar effects in beef and poultry, only 2.4 and 1.8% lactate salt was required, respectively (Meng & Genigeorgis, 1994).…”

Microbiological safety and sensory characteristics of salmon slices processed by the sous vide method

“…Over the last 10 years, several authors have studied the microbiological quality of sous vide products (Betts, 1991;Gaze, Brown, Gaskell, & Bansk, 1989;Ghazala, Aucoin, & Alkanani, 1996;Ghazala, Cosworthy, & Alkanani, 1995;Light, Hudson, Williams, Barret, & Schafheitle, 1998;Meng & Genigeorgis, 1994;Miyazawa et al, 1994;Rybka et al, 1999). However, there is very little information available on fish processed by the sous vide method, particularly on its microbiological quality (Bem Embarek & Huss, 1993;Bergslien, 1996;Garc ıa-Palacios, 1999;Gitleson, Salmarch, Cocotas, & McProud, 1992;Rosnes, Kleiberg, Bergslein, & Vidvei, 1999).…”

“…The most important pathogens in sous vide salmon are Clostridium botulinum type E and Listeria monocytogenes (Meng & Genigeorgis, 1994). Other pathogenic bacteria (Bacillus cereus and Clostridium perfringens) have been regarded as contaminants from ingredients, handling of raw materials or hygienic production conditions (Rosnes et al, 1999).…”